The invention relates to a method for the rapid deflection of a particle beam in a particle radiation optical device, particularly an electron beam writer, wherein an electrostatic and a magnetic deflection means are crossed (orthogonally disposed relative to one another) for producing deflection in a given plane and are arranged lying behind one another in the beam direction. The invention further relates to a device for implementing this method.
Lithographic generation of fine structures presently ensues in devices in which a fine or, on the other hand, already shaped particle beam--particularly an electron beam--is guided over a target to be structured. A very rapid deflection of the writing beam with frequencies up to 100 MHz is indispensible for the economical employment of such methods. In known, purely magnetic single or two-stage deflection systems, there is the problem at such high deflection speeds of constructing correspondingly rapid deflection amplifiers which are in a position to change the deflection currents with the required speed.
Although purely electrostatic deflection systems function quickly, they exhibit greater deflection errors--particularly chromatic errors--and are therefore unsuitable for generating structure over large image fields.
A combined, two-stage deflection system with an electrostatic deflection means and a magnetic deflection device lying behind it in the beam direction has already become known. In this system, a slow deflection of great amplitude is undertaken with the assistance of the magnetic deflection means and a rapid deflection of small amplitude is undertaken with the assistance of the electrostatic deflection means. To that end, the two deflection devices are driven with different signals. Therefore, there is no possibility for eliminating the extra-axial chromatic errors in addition to the geometrical errors. The chromatic errors are somewhat reduced by means of superimposing this deflection system with a projection lens (J. L. Mauer, H. C. Pfeiffer, W. Stickel, "International electron devices meeting", December 1976, Washington, pages 434-436) but, however, they are not completely eliminated.